**2.4 Staging of DR**

*Type 2 Diabetes - From Pathophysiology to Cyber Systems*

All these molecular mechanisms may lead to:

microaneurysms

*Pathogenesis of diabetic retinopathy.*

**Figure 1.**

**2.3 Clinical manifestations of DR**

Clinical signs include:

formation of lipoprotein exudates and retinal edema

the appearance of ischemic, hypoxic retinal areas.

ultimately destroying normal retinal architecture (**Figure 1**).

• alteration of tight junctions in endothelial cells, compromising the bloodretinal barrier, increasing extravasation of fluid in the retinal space and the

• thickening, hyalinization of the basement membranes, with loss of elasticity of the vascular wall and autoregulatory capacity. This, together with the alterations of blood flow and platelets, favors microvascular occlusions, with

The first areas affected by thrombosis and ischemia are in the middle retinal periphery, and the answer is to release a range of mediators, of which the key role is played by VEGF, which promotes retinal neovascularization and interruption of blood flow in many areas (optical disc, macula, iridocorneal angle and iris). The response to retinal hypoperfusion, a maladaptive protective mechanism, leads to the appearance of fragile new vessels, prone to repeated bleeding and leakage,

Fundus examination documents the presence and severity of retinal lesions.

• loss of pericytes, with the appearance of focal vascular dilations and

**254**

Dr is classically referred as: non-proliferative (NPDR) and proliferative (PDR). The classification is determined by the presence of retinal neovascularization. Recent Guidelines of International Council of Ophthalmology for Diabetic Eye Care recommends the following staging system, based on findings encountered in ophthalmoscopy, to be used in clinical practice (**Table 1**).

The ICO guidelines also refer to the location, extension of the diabetic macular edema (DME), as it is an important cause of decreased vision in DR, even in the absence of neovessels. Central involved DME is considered to be an area of retinal thickening in the macula that does involve the central subfield zone (of 1 mm in diameter).


**Table 1.**

*International Classification of Diabetic Retinopathy [57].*

#### **2.5 Clinical forms of DR associated with high risk of vision loss**

Diabetic maculopathy is the most frequent cause of decreased vision encountered in patients with T2DM. It can be manifest in every stage of the DR and represents the involvement of the fovea by hard exudates, macular edema due to fluid extravasation or by macular ischemia. In early stages, the loss of vision is mild; however, if untreated, it can may to permanent photoreceptor damage.

DME is considered clinically significant if [61–63]:


#### *2.5.1 Advanced diabetic ocular disease*

Advanced diabetic disease can remain asymptomatic for a long period of time, due to slow proliferation of the retinal neovessels and their location, usually in mid-periphery. It consists of retinal neovessels that grow into elevated fibrovascular membranes that enter the vitreous body, leading to serious complications: vitreous hemorrhage and retinal detachment [62]. Proliferation of the abnormal vessels at the level of iris and iridocorneal angle led to neovascular glaucoma, with poor clinical outcomes. Ophthalmological periodical screening is extremely important in early identifying and referral to laser therapy. In advanced stages, serious complications appear and the vision loss is irreversible.

Diabetic maculopathy is the most frequent cause of decreased vision encountered in patients with T2DM.

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**Figure 2.**

*Microvascular Complications of Diabetes Mellitus: Focus on Diabetic Retinopathy (DR)…*

Early detection of DR depends on educating DM subjects, as well as their families, friends, and health care providers about the importance of regular eye

Initial ophthalmological examination in a patient with suspected/confirmed DR

• Measurement of intraocular pressure (IOP), due to the possible risk of developing

• Slit-lamp exam +/- gonioscopy if iris neovascularization is observed or IOP is

A variety of imaging techniques are useful to detect, classify and monitor DR, as well as efficacy of treatment: fundus photography, fluorescein angiography, optic

Currently, the two most sensitive methods are retinal photography and slit-lamp examination through dilated pupils. Direct ophthalmoscopy by ophthalmologists or trained technicians yields 80% sensitivity and >90% specificity [64]. It is cheap and is considered the method of choice. Fundus photography has the advantage of creating a permanent record, and for that reason, it is the preferred method for

*"Background" diabetic retinopathy: few dot hemorrhages (blue arrows) (Dr. Ana Dascalu's private collection,* 

*Emergency University Hospital Bucharest, Ophthalmology Department).*

examination. This holds true for asymptomatic subjects as well.

*DOI: http://dx.doi.org/10.5772/intechopen.96548*

**2.6 Diagnosis of DR**

• Visual acuity

elevated

should include the following:

neovascular glaucoma

• Fundus examination with dilated pupil

*2.6.1 Ophthalmoscopy and Fundus Photography*

retinopathy assessment (**Figures 2**–**4**).

coherence tomography (OCT) and OCT angiography.

*Microvascular Complications of Diabetes Mellitus: Focus on Diabetic Retinopathy (DR)… DOI: http://dx.doi.org/10.5772/intechopen.96548*
